Positron Emission Tomography Studies with NMB in Tourette Syndrome

Grant Type
Grant Year
Institution Location
Institution Organization Name
Washington University
Investigators Name
Black, Kevin, MD

This study uses recent developments in our laboratory to address two important questions regarding Tourette Syndrome (TS): (1) are tics related to certain differences in how the brain responds to dopamine, and (2) are there biologically different subgroups of people with TS? There are several clues suggesting that in people with TS, the brain may respond differently to a chemical messenger called dopamine. For instance, drugs like haloperidol or pimozide can decrease the severity of tics. These medications prevent dopamine from talking to certain neurons in the brain by getting in the way of a class of proteins in the brain called D2-like dopamine receptors. Another example suggesting that dopamine may be involved in causing tics is that drugs which increase dopamine levels can temporarily worsen tics. Scientists have tried to measure D2-like dopamine receptors in people with TS using positron emission tomography (PET scans), but there have been conflicting results. My colleagues at Washington University School of Medicine have recently developed a new PET marker called NMB which has advantages over PET markers used previously. We will measure D2-like receptors in people with TS and in carefully matched control subjects without tics. In addition, we know that tics are not the only symptom of TS. For instance, some people with TS have obsessions or compulsions. However, most do not. At present we do not know the reason for this difference. However, there are reasons to suspect that the parts of the brain that cause obsessions may be different from those that cause tics. In recruiting volunteers for the PET study described above, we will pay close attention to the presence or absence of obsessions. We suspect there may be differences in the distribution of D2-like receptors among people with tics but no obsessions, and those with obsessions and tics. If our study is successful, we would not only know more about how the different symptoms of TS are generated in the brain, but we may also be better able to tailor treatment to the pattern of symptoms in each individual. Kevin J. Black, M.D. Washington University School Award: $39,927 Tourette Association of America Inc. – Research Grant Award 1998